OK, so here's the hat. (Please excuse the bad cell phone pic; it's the only digital camera I have on hand at the moment.)

Here's my problem--I almost never wear cream, so this hat rarely gets any use. I used to wear it with a cream suit, but that was over 20 years ago, and I've worn it maybe twice since then. However, I really love the style, and think I would get a lot more wear out of this hat if I could change it to black. I have considered dyeing it, but I have no idea if the dye would take, or what kind to try. It's a shaped felt hat with a grosgrain ribbon band, two long feathers, and net veiling. If it can't be dyed, I've considered taking the trim off and covering the hat itself with black fabric, but I've no idea how to go about it. Any ideas?

You could try dying it if it is wool (most would be). But it would lose its shape and need to be reblocked and possibly starched. You could try covering it. Hand draping fabric over the top and piecing it together could get a fairly decent fit. Making an outer hat band could cover some of the seams, doing a grosgrain ribbon edge on the end of the brim would afford another way of covering fabric ends or seams.

Thanks for all the input! A spray dye or fabric paint does seem like it might be safest, and if that ends up not working out, I suppose I could always try covering it. I think as long as I can preserve the basic shape of the hat, I can always replace the trim if it gets messed up.